Method for forming piles



Jan. 3', 1956 R. PATTERSON METHOD FOR FORMING FILES Filed Sept. 18, 19512 Sheets-Sheet Jan. 3, 1956 R. PATTERSON 2,729,067

METHOD FOR FORMING FILES Filed Sept. 18, 1951 2 Sheets-Sheet 2'l/III/Il/III/II/IIIII/I/I/ I I r i I 23 Fig. 5

INVENTOR Raynwnol Patterson ATTORNE U ed States Patent" 2 ,729,067METHOD non FORMING mans Raymond-Patterson, Evergreen Park, 111.,as'signor, by mes'ne assignments, to 'Intrusion-Prepakt, Incorporated,

(newsman, .Ohio,- a corporation of Delaware Application September18,1951,.Serial No. 247,151 12' Claims. c1. iii-57 This inventionrelates to the forming of concrete piles inthe earthand particularly tosimplified and improved mt hods and apparatus for forming. concretepiles in all kinds ofearth formations, other than solid rock formations.7

Numerous methods and types of apparatus have been employed heretoforefor forming or constructing concrete t piles in the earth, The methodsand apparatus employed haveva-riedgreatly according'tothe particularconditions under which thework must be performed, the character of theearth formations to bepenetrated, and the type and magnitude of theloads to be supported" or forces to be resisted; All of such methods andapparatus, how ever, have been subject in varying degrees to limitationsrestricting their use to certain types of working condi-- tions, earthformations, and load resisting requirements.

Many of the methods have required the use of ex-- 21 Because of: thevarious shortcomings of prior methods and apparatus, many projectshavehad' to lee-abandoned as economicallyunfeasible, or structuresliavehad to be specially des-igned'at. great expense to compensatefo'r the;shortcomings of the pile: supports that could be provided by=knowntechniques The general object of the present invention is toprovideimproved methods and apparatus for constructing piles in earthformations; whicliv'methodszand apparatus are; applicable underconditions that preclude; the'iuse of many, types of prior methods andapparatus, are cheaper and faster toemploy, and produce superiorresults.

More w specific objects'of' the'invention are to provide methodsandapparatusfor constructingrconcr'ete piles in looseand unstable: earthformations'without tlie use" of any-kind-of casing, withamihimumof'headroomabove ground, and with the use of: only small and-relativelyinexpensive equipment.

Another object of the invention is to provide methods and apparatusfor'constrncting piles inearthformations without the need forflapplyingvertical forces for driving apparatus .or. objects. into the-earth: orfor withdrawing:

themafromthe earth 'iHt-thCzCOUfSB of the work.

Anotherobjectot"; the invention is to provide methods and ,apparat'usforconstructing: piles in'loose and unstableearth formationsv that lack.adequate bed-rock support while. obtaining greater resistance ;to.sinking of the piles- 7 under vertical loads. I j

- Another object of the invention is toproduce in loose or porous earthformations'concrete piles having later- 2 ally extended monolithicprojections that fill existing voids in the earth formations around thepiles along substantially the full vertical height of the piles.

A turther'object of the invention is to provide methods and apparatusfor constructing piles in loose and unstable earth formations in such amanner that the loose earth masses around the piles are compactedlaterally away from the piles, thus providing bulbous, monolithicprojections on the pilesthat extend laterally into such masses to givevertical support to the piles while stabilizing the surrounding earthmasses.

Still another object of the invention is to construct piles in the earththat are particularly efiective when con structed adjacent each other toform more or less continuous walls of concrete extending around or alongun stable earthmasses.

Stillanother object of the invention is to accomplish the foregoingobjectives without the necessity for leaving expensive equipment in theearth as a part of the finished pile structures= I A characteristicfeature-of the invention by which the foregoing objects are=accomplishedinvolves the use of an auger-type drill that is sunk into the earth todefine the location and depth of the cavity in which a pile is to beconstructed and the minimum lateral dimensions of the pile.- The augeractionzof the drill permitssit to be sunk to the desired depth withoutremoving the earth from the cavity, the auger blade and the cylindricalmass of earth through which it passes acting'tog'ethe'r as a" plugfilling the space to be subsequently occupied by the pile. A hydrauliccement grout. is then pumped into the earth below the lower'end of thedrill, either through a grout pipe jetted to substantially the samedepth closely adjacentthe drill. or through the drill shaft itself. Thegroutis pumped with sutficient pressure to cause it to slowly raise thedrill and the earth penetrated by the drill vrt'i cally out of the earthmass as the grout fills the cavity originally defined-by the drill, andthe pumping of the grout is continued until it has filled the cavitysubstarl tially tothe ground level, or to any lower level at which thetop of thepile isto' belocated.

The combined weight of the drill and the earth re tained thereby keepsthe grout under'pressure throughout the pile casting operation andinsures completefilling of the originally defined cylindrical cavitywith a dense concrete having a minimum of voids; In addition, the groutpressure maintained in the cavity in this manner acts outwardly inalldirections and compacts surrounding loose, sandy strataaway from thepile with the formation of bulbous, laterally extending, monolithic prase tions on the pile body. This interlocks the pile with the firmerstrata, greatly" increasing the resistance of thepile' to'sinking undervertical'loads, and gives the pile: greater lateralsupport againsttilting due to eccentric loads by densifying the surrounding loosestrata. The grout'a'ls'o flows outwardly in'alldirections into allcracks, crevices, and interstices of the surrounding earth formations,whether they are loose and unstable or relatively rigid and-stable;thus-forming a-multiplicity of smaller; lateral,

monolithic projections of the pile bodythat give still further verticalandlateralsupportto the'pile and that solidify and stabilize'the entiresurrounding earth mass.

According to preferred practice, particularly when workingwith limitedhead room above ground, the augertypedrill is made up-of short sections,four feet or so in length, thati are'assembl'ed'one-by" one in' endto-end relation as the anger is sunk into the earth and thatjaredisassembled in'th'ereverse' order as thedrill is forced out of theearth again by thepressure of the'groutintro this case, in order tomaintain the grout under pressure and prevent it from being forced backout of the cavity by the weight of the earth-loaded drill string, it ismost convenient to introduce the grout into the pile cavity through aseparate pipe that is jetted or otherwise sunk into the earth beside thedrill, as mentioned above. Alternately, of course, the hollow shaft ofeach drill section may be provided with any suitable type of check valveto prevent the reverse flow of grout therethrough.

The employment of an auger-type drill in accordance with the inventionhas still other advantages. Because it is propelled in a downwarddirection by its spiral blade and by its own weight when rotated, novertical forces need be applied to sink it into the earth. Thisdispenses with the need for massive pile driving equipment, reduces thehead room required by such equipment, and eliminates the vibration thatis inherent in the operation of such equipment and is often damaging inits efiects on surrounding structures and formations. Also, since theauger cuts its way into the earth without any material compacting actionagainst the cavity walls, there is no tendency to so densify the earthimmediately adjacent the cavity as to seal it against penetration by thegrout. Thus, maximum freedom of the grout to penetrate cracks, crevices,and interstices of the surrounding formations for great distances isinsured, with the benefits explained above.

While I prefer to use an auger type drill made up of short sections,each of which carries an anger blade running spirally about the shaftthereof for substantially its full length, as hereinafter described, theinvention is not to be construed as limited to the use of such a drillexcept as the claims may so require. Satisfactory results may beobtained if the drill has an anger type cutting blade at its lower endthat makes at least one full convolution about the shaft and is,therefore, capable of providing ample support for the cylindrical massof earth penetrated thereby over the entire transverse cross section ofthe pile cavity to raise the earth out of the cavity in accordance withthe invention.

The foregoing and still further objects, advantages, and features of theinvention will be better understood, or will become apparent, from thefollowing detailed description of preferred apparatus and methods forcarrying out the invention, and from the accompanying drawing in which:

Figure 1 is a vertical section through an earth mass in which a pile isto be constructed during an early stage in the construction of the pile,with the drilling apparatus employed shown partially sunk into the earthmass;

Fig. 2 is a fragmentary vertical section on an enlarged scale showing,in more detail, a portion of the apparatus of Fig. 1, sunk into theearth mass to the full depth of the pile;

Fig. 3 is a similar sectional view showing additional apparatus employedat a later stage in the construction of a pile and showing the lowerportion of the pile cavity filled with concrete and the drillingapparatus partially removed.

Fig. 4 is a similar vertical sectional view through the finished pile;

Fig. 5 is a vertical sectional view through the lower end of a modifiedform of auger-type drill for use in accordance with the invention;

Fig. 6 is a fragmentary horizontal section showing details of theapparatus of Fig. 5, the section being taken as indicated by the line6-6 of Fig. 5;

Fig. 7 is a vertical sectional view through another portion of theapparatus of Fig. 5, showing how a series of anger sections may besecured together in end to end relation;

Fig. 8 is a horizontal section through the apparatus of Fig. 7, thesection being taken as indicated by the line 8-8 of Fig. 7; and

Fig. 9 is a fragmentary vertical section through the lower end of stillanother modified form of auger-type drill adapted for use in accordancewith the invention.

Referring first to Fig. 1, an auger-type drill, generally designated 11,is shown sunk into the earth to a portion of the depth of a pile cavity12 (shown in phantom outline) to be drilled in an earth mass 13. Thedrill 11, being of the auger type, requires only to be rotated to cutits way into earth masses other than more or less solid rock, and it mayconveniently be rotated by any suitable motor 14 coupled thereto andhaving handle bars 16 and 17, or the like, attached thereto for manuallyholding the motor itself against rotation. With larger equipment anddeeper pile cavities to be drilled, the motor may be more securely heldby any convenient structure (not shown). The motor shaft is preferablycoupled to the drill shaft 18 by a simple sliding fit permitting quickcoupling and uncoupling by merely lowering and raising the motor, as bymeans of a sleeve 19 on the lower end of the motor shaft having a squareor other non-circular bore and a complementary shaped end 20 on theupper end of the drill shaft closely embraced by the sleeve 19.

The drill 11 is preferably comprised of a plurality of relatively shortlengths, as stated above, each length having a sleeve, like the sleeve19, mounted on one end of its shaft and a complementary shaped, squareor other non-circular opposite end 20 to be embraced by the socket ofthe adjoining drill section with a close sliding fit. Each sleeve 19 maybe either permanently or removably secured to the shaft 18 of one drillsection as by a suitable pin 21, and adjoining drill sections arepreferably secured together by means of a tapered pin 22 so as to permitrapid assembly and disassembly of the drill string. The drill sectionsmay all be identical and of conventional design, with an auger blade 23spiralling about the central shaft 18 from end to end thereof.Alternately, if desired, the lowermost drill section may have the lowerend of its shaft equipped with a lead screw 24, preferably removable forreplacement, and a special cutter blade 25 and supporting structure 26therefor (Fig. 5), the special cutter blade being removable forsharpening or replacement. Since the detailed construction of the drillmay be conventional for carrying out the invention as illustrated inFigs. 1 to 4, a minimum of such details is shown for the sake ofsimplicity.

The drill 11 is screwed into the earth while connecting section aftersection thereof in end-to-end relation as required to keep the upper endof the drill above the surface where it may be driven by the motor 14 asthe lower end of the drill moves downwardly. Where feasible, the drillis sunk until solid rock is encountered. Otherwise, the depth to whichthe drill is sunk is determined largely by the load resistingrequirements of the finished pile and the character of the earthformations penetrated, which effect the load resisting capacity of thefinished pile, as explained above.

When the drill has been sunk to the depth required to define the generaldimensions and location of a pile cavity to be formed, the drill is leftin place with the earth bounded by the defined limits of the pile cavityretained between successive convolutions of the drill blade. The drilland the earth so retained thereby thus together constitute, in effect, aplug that completely fills the cavity to be formed.

At this point, a grout feeding pipe, preferably comprised of a pluralityof sections 28 connected together as shown (Fig. 3), is driven into theearth closely adjacent the drill 11 by hammering or jetting. When thispipe is driven by hammering, it is desirable to temporarily close thelower end thereof with a suitable, loosely fitting cap or plug (notshown) to prevent soil and gravel from entering and packing in the pipe.Either water or intrusion materials may be pumped through the groutfeeding pipe to hydraulically dig the hole for the pipe in accordancewith known practices. The grout feeding pipe may also be assembledsection by section as it is sired point aroundy'the' drill 5 proj'ictedjdowiiwardly, partic 'l" l limited head-room above oun The grout feedingpipe rii be inserted from any de- 0 long as: it is directed to bringithe lewer end of the pipe into close proximity with the lower end of thedrill, preferably at or slightly below the depth to which the drill hasbeen sunk. A source (not shown) of a suitable, fluid grout isthen'connected through a suitable pump (not shown) to the upper end ofthegrout feeding pipe, and grout is pumped under relatively highpressurethrough the pipe and into the earth adja cen fthe lower end ofthe drill, fromwhence it will new in any direction through existingcracks,

when required by crevices, and interstices of-tliesurroundingformations,

sooner or later penetrating the region immediately below the dam As thevoids in this general region become filled was; grout and the grout isforced farther and farther outwardly in one ormore" directions; theresistance to its new; increases; and-the pressure in; the immediatevicinity of the lowerends-of the drill and grout pipe increases,eventually developing sufii'c-ien't-force against the lowereud of theearth loaded drill to raise it slowly as the pumping 'o'f grout iscontinued. The previously. defined pile cavityii s' thus filled withgrout frointhe bottom upwardly unde r high-{pressuremaintained by theearthloaded drill" asthe drill rises. The pressure at any depth is, ofcourse,- roughly proportional to-the weight of the earth-loaded drilland the frictional .forces resisting its rise,-p,lus the weight ofanygrout above that depth, per unit areaor the drillbot-tom. The drillsections maybe disconnectedone by one as they emerge above the groundlevel, and the earth carried thereby may be removed, thus graduallyreducingthe' back pressure on the grout and eifectinga graduallydecreasing pressure-gradient in the gr ou tflfilled cavity from thebottom toward the-top. This avoids any danger of shooting largequantities of grout upwardly out of the cavity around the drill.

By reason of the grout pressure within-the pile cavity, the grout is"forced-into-cracks, crevices, and interstices of the surroundingearth-formations in-all directions along the major part of the length ofthe pile from the grout is fed-with; only minor friction QSscs directlyto the bottom of the; pile cavity, it'is'applied with substantially thefullpumping pressure precisely whereit is needed the most.Driving'forces applied downwardly on masses of preplaced aggregate,-and*grout pressures applied bypumping groutdownwardly through a mass ofpreplaced aggregate, are, by contrast, largelydissipated by frictionallosses, etc., and onlyrelatively small forces and pressures are actuallyapplied at the bottom of the pile and are relatively ineffective foraccomplishing the above described results.

Thus, the benefits of constructing a pile in this manner are numerous,both as regards the strength and density I of the solidifiedconcrete ofwhich the pile itself is made bottoni end thereof. This solidifies andrigidifies porous surrounding masses, particularly below the pile andround the lower pojrtions of the pile, giving greater lateral andvertical' support to the pile and increasing the load carrying capacityofthe surrounding earth. The monolithic character or all thegroutsupplied, both within and beyond the boundaries of the pile cavityitself,- for-msain effect an enlarged pile base. and interlocks the pilewith the surrounding earth formations along the length-of the pile, thusfurther increasing the resistance to vertically applied loads,particularly when the pile does not rest on bedrock; Inaddition, looseporous masses adjoining the pile cavity are compacted and compressedaway from the cavity so as to form bulbous enlargements of thefcavityhere and there along its originally defined boundary. This compactingaction and the consequent filling of the enlargementsso formed alsocontributes subst antially'toboththe vertical and lateral support of thepile.

Depending largely upon the depth-to which the drill has been sunk, thegrout pressures may range from as low as or -lbs./ sq. in. to as high as400 or more lbs/sq. in. When workingin earth formations of averagedensity, thepressure requiredjtolift the eartlnloaded drill string isabout *2 lbs/sq. in. per linear foot of the drill string In the majorityof cases, accordinglo my experience, pumping pressures in the range fromabout 30,lbs./sq. in. t0 '12 0 lbs/sq. in. will suffice, and pressuresas high as 400"lbs./sq. in. willbe required only for building piles ofunusually great depth.

Though'pressures of the orderof 30 to lZ-ftlbs/sqin. are relatively low,they are highly etlieient'in compacting and densifying the lower starata where the major portion of the vertical load is normally applied.Because the and the imperviousness, rigidity, and general stability ofthe surrounding earth for considerable distances from the pile body.Becauseqof these effects, a plurality of such piles formed side by sideare most effectiveas retaining walls around unstable earthmasses andasbarriers to the seepage of water.

As explained above, the grout pumped into the earth below the lower endof the drill may be conveyed to that region through the shaft of thedrill itself, rather than through a separate pipe sunk into the earthbeside the drill. This, of course, requires a drill having a hollowshaft that is open at its lower end for discharge of the grout pumpedtherethrough. During the sinking of such a drill, the lower end of theshaft may be closed to prevent the forcing of earth into the hollowshaft and thereby plugging it so as to, impede the flow of grouttherethrough. This maybe accomplished with any of a number of closurearrangements, one simple form of which is illustrated in Fig. 5.

Referring to Fig. 5, there is shown a hollow drill shaft 31 having anauger b1ade32'mounted thereon. The special cutter blade 25,*removablymounted in the sup porting structure 26 thereof, is shown attached tothe 4 lower end of the drill shaft by means of a hollow sleeve 33' and aplurality of bolts or pins 34. The blade supporting structure26is'shaped to provide a shoulder 36 thatbears against the lower end ofthe hollow drill shaft 31 and a conical seat 37 for. a plug 38'having acorrespondingly tapered shoulder 39 and a cylindrical portion 41 thatprojects into the cylindrical interior of thesleeve 33; Abutment of thetapered periphery 39 of the plug 38 with the correspondingly taperedshoulder 3'1 of the sleeve 33 prevents theplug from being forced intothe drill shaft 31 as the drill is sunk into the earth;

The plug may be restrained from falling out of the blade supportingstructure 26 in any desired manner that willpermit it to be easilyejected by the application of pressure to the upper end of the plug bythe grout to be pumpedthrough the drill shaft. A pair of shear pins 42of soft metal, such as lead, may be inserted for this purpose throughaligned apertures drilled through the walls of the hollow drill shaft 31and sleeve 33 and into the cylindricaliportion 41of the plug 38, Thesepins are easily sheared otf by pressure exerted against the inner end oftheplu'g 38. V

in the event it is desired to employ a lead screw on the lower end ofthe lower drill section, this may be accomplished by securing a leadscrew 43 to a modified plug 44 in any desired manner, as by welding.Rotation of the leadscr'ew 43 and the plug44 in a blade supportingstructure 45 may be prevented by providing a square or other noncircularbore 46 through the sleeve portion of the blade supportingstructure 45 and making the plug 44 of corresponding cross-sectionalconfiguration, as shown in Fig. 9. In other respects, the plug, theblade supporting structure, and the drill sleeve assembly may be thesame asthe assembly shown in Figs. 5 and 6.

Adjoining sections of, the drill string may be connected together so asto permit the application of a driving torque from one section of thedrill string to the next by welding a sleeve 47, having a square orother non-circular internal socket 48, on one end of each section of thedrill string, and a sleeve 49 on the opposite end of each section, thesleeve 49 having a hollow projection 51 of complementary, square ornon-circular, exterior shape to be received with a close sliding fit inthe socket 48 of the sleeve 47 on an adjoining drill section. Each pairof interfitting sleeves 47 and 49 may be locked together by means ofbolts or pins 52.

When employing drill sections with a hollow shaft for conveying thegrout into the earth below the drill string, it is not convenient todisassemble the drill string section by section as it is ejected fromthe earth by the grout pumped into the pile cavity unless specialprovision is made for disconnecting the grout supply line and blockingthe reverse flow of grout through the drill string while each drillsection is being removed. Accordingly, the introduction of grout throughthe drill string is preferably employed only in forming relativelyshallow piles requiring the use of a relatively short drill string, orin situations where there is sufficient head room above ground to permitthe entire drill string to be removed without disassembling it assection after section emerges from the pile cavity.

In other respects, operation of the pile forming process issubstantially the same whether the grout is introduced into the earththrough a separate grout conduit sunk adjacent the drill or isintroduced into the shaft through the drill itself.

The grout employed in accordance with the present invention should be ofa highly fluid consistency with as low a viscosity as can practically beobtained while retaining the essential characteristics of high strengthin the solidified concrete. A grout having these characteristics to anoutstanding degree is described in United States Patent No. 2,434,302,granted January 13, 1948, to Louis S. Wertz. Such a grout consistsessentially of water having dispersed therein a high strength hydrauliccement, such as Portland cement; fine sand in an amount up to abouttwice the amount of cement by weight; a finely divided gas producingmaterial, such as aluminum powder, in an amount from about 0.005% toabout 0.05% of the amount of cement by weight; a finely dividedinorganic filler, such as fiy ash, blast furnace slag, pozzolanas, andother finely divided, natural or artificial, siliceous materials, in anamount from about to 2 or 3 times the amount of cement by weight; and alubricating and/ or suspending agent to increase flowability.

At least some of the finely divided inorganic filler preferably containsacidic colloidal silica to retard the gelation or setting of the cement.

The lubricating agent may be any of a wide variety of oleaginousmaterials, such as mineral oils, stearates, natural or sulfonatedvegetable oils, and mixtures thereof. The amount of these lubricatingagents required will vary somewhat with the type selected and theflowability desired, but will usually be between about 0.1% and 2.0% ofthe weight of the cement. Since these lubricants also act as setretardants and, in large amounts, tend to weaken the solidifiedconcrete, their quantity should be less than 2% in most instances.

In addition to the above ingredients, the grout may contain a smallamount of a cement dispersing agent, such as a lignin sulfonic acidresidue, and other conventional additives. Also, as disclosed in thecopending patent of Louis S. Wertz, Number 2,655,004 dated October 13,1953, for Composition for and Method of solidifying Porous Masses andStructures, a water-soluble cellulose ether, such as methylcellulose orsodium carboxymethylcellulose, may be employed to great advantage invery small amount as a substitute for all or most of the olcaginous rtypes of lubricating agents. In amounts of about 0.005% to about 0.25%of the weight of the total solids in the grouts, these cellulose etherslubricate the grouts without any noticeable increase in viscosity andwithout deleteriously affecting the strength of the set concrete. They 8reduce the water gain and rate of water extraction of the grouts and areexcellent suspending and lubricating agents.

From the foregoing description it will be appreciated that the inventionaccomplishes the various objectives and advantages described above in asimple manner admirably adapted for use under a wide variety ofconditions. While specific examples of the method and of certain specialapparatus for use in carrying out the method have been described indetail, it will also be appreciated that numerous modifications thereofmay be employed by those skilled in the art while following the generalprin' ciples of the invention and without departing from the scopethereof as defined in the appended claims.

Having described my invention, I claim:

1. A method of forming piles in the earth comprising sinking anauger-type drill into the earth to define the location and depth of apile cavity without removing the earth therefrom, and forcing a fluidhydraulic cement grout into the earth below said drill with sufficientpressure and in sufficient quantity to raise said drill from said cavityand form the pile therein.

2. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity while retaining the earth in said location, and forcing afluid hydraulic cement grout into the earth below said drill and intocontact with the lower end thereof with sufiicient pressure and insufiicient quantity to raise said drill and earth from the pile cavityand simultaneously to fill with grout both said cavity and voids in theearth communicating therewith.

3. A method of forming piles in the earth comprising sinking anauger-type drill into the earth to define the location and depth of apile cavity without removing the earth therefrom, and forcing a fluidcementitious mixture into the earth below said drill with suflicientpressure and in sufiicient quantity to exert an upward raising force onsaid drill, while restraining the drill from rotation in said cavity, toform the pile therein, said drill having a hollow shaft, and saidmixture being fed into the earth below said drill through said hollowshaft.

4. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity while retaining the earth in said location, and forcing afluid hydraulic cement grout into the earth below said drill and intocontact with the lower end thereof with sufiicient pressure and insufiicient quantity to exert an upward raising force on said drill andearth in the pile cavity, while restraining the drill. from rotation,thereby filling with grout both said cavity and voids in the earthcommunicating there with, said drill having a hollow shaft, and saidgrout being fed into the earth below said drill through said hollowshaft.

5. A method of forming piles in the earth comprising sinking anauger-type drill into the earth to define the location and depth of apile cavity without removing the earth therefrom, sinking a pipe intothe earth adjacent said location to a depth at least substantially asgreat as the depth of the lower end of said drill, and forcing a fluidhydraulic cement grout, through said pipe and into the earth below saiddrill with suflicient pressure and in suflicient quantity to raise saiddrill from said cavity and form the pile therein.

6. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity while retaining the earth in said location, sinking a pipeinto the earth adjacent said location to a depth at least substantiallyas great as the depth of the lower end of said drill, and forcing afluid hydraulic cement grout through said pipe and into the earth belowsaid drill and into contact with the lower end thereof with sufiicientpressure and in sufiicient quantity to raise said drill and earthtogether out of the pile cavity and simultaneously to fill with groutboth said cavity and voids in the earth communicating therewith.

7. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity while retaining the earth in said location, said drillhaving a shaft composed of sections coupled together in end-to-endrelation, forcing a fluid hydraulic cement grout into the earth belowsaid drill and into contact with the lower end thereof with sutficientpressure and in suflicient quantity to raise said drill and earth fromthe pile cavity and simultaneously to fill with grout both said cavityand voids in the earth communicating therewith, and disconnecting andremoving the drill shaft sections one-by-one as they emerge from thepile cavity to effect a stepwise reduction in the back pressuremaintained on the grout by the drill and the earth raised therewith.

8. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity, said drill having an auger-type blade spiralling upwardlyfrom the lower end thereof for a plurality of continuous convolutions toretain earth in said location between successive convolutions of thedrill blade, said drill having a shaft composed of sections coupledtogether in end-to-end relation, sinking a pipe into the earth adjacentsaid location to a depth at least substantially as great as the depth ofthe lower end of said drill, forcing a fluid hydraulic cement groutthrough said pipe and into the earth below said drill and into contactwith the lower end thereof with suflicient pressure and in sufiicientquantity to raise said drill and the earth retained between successiveconvolutions of the drill blade and supported thereon from the pilecavity and simultaneously to fill with grout both said cavity and voidsin the earth communicating therewith, and disconnecting and removing thedrill sections oneby-one as they emerge from the pile cavity to effect astepwise reduction in the back pressure maintained on the grout by thedrill and. the earth raised therewith.

9. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity while retaining the earth in said location betweensuccessive convolutions of the drill blade, said drill being composed ofdrill sections coupled together in end-to-end relation, driving a pipeinto the earth in a direction to bring one end thereof closely adjacentthe lower end of the drill, forcing a fluid hydraulic'cement groutthrough said pipe and into the earth below said drill and into contactwith the lower end thereof with sufiicient pressure and in sulficientquantity to raise said drill and the earth retained between successiveconvolutions of the drill blade from the pile cavity and simultaneouslyto fill with grout both said cavity and voids in the earth communicatingtherewith, and disconnecting and removing the drill sections one-by-oneas they emerge from the pile cavity to effect a stepwise reduction inthe back pressure maintained on the grout by the dirll and the earthraised therewith.

10. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity, said drill having an auger-type blade spiralling upwardlyfrom the lower end thereof in a series of substantially continuousconvolutions extending substantially the full depth of said cavity forretaining and supporting the earth in said location between successiveconvolutions of the drill blade, and forcing a fluid hydraulic cementgrout into the earth below said drill and into contact with the lowerend thereof with suflicient pressure and in sufiicient quantity to raisesaid drill and the earth retained between successive convolutions of thedrill blade from the pile cavity and simultaneously to fill with groutboth said cavity and voids in the earth communicating therewith.

11. A method of forming piles in the earth comprising screwing anauger-type drill into the earth to define the location and depth of apile cavity, said drill being composed of drill sections coupledtogether in cnd-to-end relation and each of said drill sectionscomprising a shaft having an auger-type blade spiralling about the shaftsubstantially from end to end thereof, whereby the earth in saidlocation is retained between and supported by successive convolutions ofthe drill blade for substantially the entire depth of the cavity,forcing a fluid hydraulic cement grout into the earth below said drilland into contact with the lower end thereof with sufiicient pressure andin suflicient quantity to raise said drill and the earth retainedbetween successive convolutions of the drill blade from the pile cavityand simultaneously to fill with grout both said cavity and voids in theearth communicating therewith, and separating and removing the drillsections one by one as they emerge from the pile cavity to effect astepwise reduction in the back pressure maintained on the grout by thedrill and the earth raised therewith.

12. A method of forming piles in the earth comprising screwing anauger-type drill to sink it into the earth to define the location anddepth of a pile cavity while retaining the earth in said location,forcing a fluid hydraulic cement grout under pressure into a space belowsaid drill to exert a removing force on the drill while restrainedagainst rotation in an unscrewing direction, the grout being supplied insutficient quantity to fill the cavity created by the withdrawal of saiddrill and form a pile.

References Cited in the file of this patent UNITED STATES PATENTS2,025,354 Masclek Dec. 24, 1935 2,034,075 Wright Mar. 17, 1936 FOREIGNPATENTS 41,295 Austria 1910 65,615 Austria 1914 338,010 Italy 1936

